feat: implement type-safe ReferenceProperty for SmartPointer fields and add UI support for object selection via context-aware dropdowns

src/Core/Property.h

@@ -15,6 +15,15 @@
 #include "Core/Archives.h"
 #include "Core/Signal.h"
 #include "Core/Object.h"
+#include "Core/SmartPointer.h"
+
+// Type traits for detecting SmartPointer<T>
+namespace uLib {
+template<typename T> struct is_smart_pointer : std::false_type {};
+template<typename T> struct is_smart_pointer<SmartPointer<T>> : std::true_type {};
+template<typename T> struct smart_pointer_element { using type = void; };
+template<typename T> struct smart_pointer_element<SmartPointer<T>> { using type = T; };
+} // namespace uLib
 
 namespace uLib {
 
@@ -216,6 +225,109 @@ private:
 
 } // namespace uLib
 
+namespace uLib {
+
+/**
+ * @brief Base class for reference properties (SmartPointer<T> fields).
+ * Provides a type-erased interface for getting/setting object references
+ * and checking type compatibility.
+ */
+class ReferencePropertyBase : public PropertyBase {
+public:
+  virtual ~ReferencePropertyBase() {}
+  virtual Object* GetReferencedObject() const = 0;
+  virtual void SetReferencedObject(Object* obj) = 0;
+  virtual bool IsCompatible(Object* obj) const = 0;
+  virtual const char* GetReferenceTypeName() const = 0;
+};
+
+/**
+ * @brief Typed reference property for SmartPointer<T> fields.
+ * Filters context objects by dynamic_cast compatibility with T.
+ */
+template <typename T>
+class ReferenceProperty : public ReferencePropertyBase {
+public:
+  ReferenceProperty(Object* owner, const std::string& name, SmartPointer<T>& ref,
+                    const std::string& units = "", const std::string& group = "")
+    : m_owner(owner), m_name(name), m_units(units), m_group(group), m_ref(ref), m_ReadOnly(false) {
+      if (m_owner) m_owner->RegisterProperty(this);
+  }
+
+  virtual ~ReferenceProperty() {}
+
+  // PropertyBase interface
+  virtual const std::string& GetName() const override { return m_name; }
+  virtual const char* GetTypeName() const override { return typeid(SmartPointer<T>).name(); }
+  virtual std::type_index GetTypeIndex() const override { return std::type_index(typeid(ReferencePropertyBase)); }
+  virtual const std::string& GetUnits() const override { return m_units; }
+  virtual void SetUnits(const std::string& units) override { m_units = units; }
+  virtual const std::string& GetGroup() const override { return m_group; }
+  virtual void SetGroup(const std::string& group) override { m_group = group; }
+  virtual bool IsReadOnly() const override { return m_ReadOnly; }
+  void SetReadOnly(bool ro) { m_ReadOnly = ro; }
+
+  virtual std::string GetValueAsString() const override {
+    T* ptr = m_ref.Get();
+    if (!ptr) return "(none)";
+    Object* obj = dynamic_cast<Object*>(ptr);
+    if (obj) {
+      std::string iname = obj->GetInstanceName();
+      if (!iname.empty()) return iname;
+      return obj->GetClassName();
+    }
+    return "(set)";
+  }
+
+  // ReferencePropertyBase interface
+  virtual Object* GetReferencedObject() const override {
+    return dynamic_cast<Object*>(m_ref.Get());
+  }
+
+  virtual void SetReferencedObject(Object* obj) override {
+    if (!obj) {
+      m_ref = SmartPointer<T>(nullptr);
+      this->Updated();
+      if (m_owner) m_owner->Updated();
+      return;
+    }
+    T* casted = dynamic_cast<T*>(obj);
+    if (casted) {
+      m_ref = SmartPointer<T>(casted);
+      this->Updated();
+      if (m_owner) m_owner->Updated();
+    }
+  }
+
+  virtual bool IsCompatible(Object* obj) const override {
+    return dynamic_cast<T*>(obj) != nullptr;
+  }
+
+  virtual const char* GetReferenceTypeName() const override {
+    return typeid(T).name();
+  }
+
+  // Serialization stubs
+  virtual void serialize(Archive::xml_oarchive & ar, const unsigned int v) override {}
+  virtual void serialize(Archive::xml_iarchive & ar, const unsigned int v) override {}
+  virtual void serialize(Archive::text_oarchive & ar, const unsigned int v) override {}
+  virtual void serialize(Archive::text_iarchive & ar, const unsigned int v) override {}
+  virtual void serialize(Archive::hrt_oarchive & ar, const unsigned int v) override {}
+  virtual void serialize(Archive::hrt_iarchive & ar, const unsigned int v) override {}
+  virtual void serialize(Archive::log_archive & ar, const unsigned int v) override {}
+  virtual void serialize(Archive::property_register_archive & ar, const unsigned int v) override {}
+
+private:
+  Object* m_owner;
+  std::string m_name;
+  std::string m_units;
+  std::string m_group;
+  SmartPointer<T>& m_ref;
+  bool m_ReadOnly;
+};
+
+} // namespace uLib
+
 namespace uLib {
 namespace Archive {
 
@@ -267,7 +379,20 @@ public:
     }
 
     template<class T> void save_property_impl(const char* name, T& val, const char* units, bool hasRange, const T& minVal, const T& maxVal, bool isReadOnly) {
-        if (m_Object) {
+        if (!m_Object) return;
+        if constexpr (is_smart_pointer<T>::value) {
+            // SmartPointer<U> field: create a ReferenceProperty<U> for type-safe selection
+            using ElementT = typename smart_pointer_element<T>::type;
+            auto* p = new ReferenceProperty<ElementT>(m_Object, name, val, units ? units : "", GetCurrentGroup());
+            p->SetReadOnly(isReadOnly);
+            if (m_DisplayOnly) {
+                m_Object->RegisterDisplayProperty(p);
+                Object* obj = m_Object;
+                Object::connect(p, &Object::Updated, [obj]() { obj->Updated(); });
+            } else {
+                m_Object->RegisterDynamicProperty(p);
+            }
+        } else {
             Property<T>* p = new Property<T>(m_Object, name, &val, units ? units : "", GetCurrentGroup());
             set_range_helper(p, hasRange, minVal, maxVal, typename std::is_arithmetic<T>::type());
             p->SetReadOnly(isReadOnly);